Mineral Precipitate (Anthropogenic Context)

Ironstone Concretion (Limonite/Hematite Nodules)

Ironstone (principally Limonite FeO(OH)·nH2O or Hematite Fe2O3 mixed with silica/clay)

Ferruginous Sandstone (Red Sandstone)

Arenite with Hematite/Limonite cement

Ferruginous Quartz (Iron-stained Quartz)

Silicon Dioxide (SiO2) with Hematite/Goethite inclusions

Red Sandstone

Arenite (Ferruginous Sandstone)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Limonite and Goethite (Ironstone)

Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)

Quartz Pebble

Silicon Dioxide (SiO2)

Jasper with Manganese Dendrites

Silicon Dioxide (SiO2) with Oxide Mineral Inclusions

Brecciated Chert

Sedimentary Chert (SiO2) with Calc-Silicate mineralization

Jasper (var. Ocean or Polychrome Jasper)

Silicon Dioxide (SiO2) with iron and mineral inclusions

Rutilated Prehnite

Prehnite - Ca2Al(AlSi3O10)(OH)2 with Epidote/Tourmaline inclusions

Quartzite (with Iron Staining)

Metamorphosed Quartz Sandstone (SiO2)

Carnelian

Chalcedony (SiO2) with iron oxide impurities

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Blue Quartz (Aventurine)

Silicon Dioxide (SiO2) with fibrous inclusions (commonly Dumortierite)

Quartz Pebble

Silicon Dioxide (SiO2)

Blue Apatite

Apatite (Ca5(PO4)3(F,Cl,OH))

Chert (Red Jasper variant)

Microcrystalline Quartz (SiO2)

Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Epidote

Epidote (Ca2(Al,Fe)3(SiO4)3(OH))

Astrophyllite

Potassium Sodium Iron Manganese Titanium Silicate Hydroxide (K3NaFe7Ti2Si8O24(OH)7)

Geode (unopened)

SiO2 - Chert-shelled concretion (mostly Quartz)

Corundum (Ruby Variety)

Corundum (Al2O3)

Epidote (likely Unakite component or Epidosite)

Epidote (Ca2(Al2Fe)(SiO4)(Si2O7)O(OH))

Schist

Mica Schist

Granite

Phaneritic Igneous Rock (Granite)

Sandstone (Quartzose type)

Arenite (primarily SiO2)

Amygdaloidal Basalt with Epidote

Vesicular Basalt with secondary Epidote/Quartz mineral infill

Lapis Lazuli

Na8[Al6Si6O24]Sn (Lazurite-rich metamorphic rock)

Lapis Lazuli (Low-grade/Calcite-heavy)

Na8[Al6Si6O24]n(S,Cl,SO4,OH)2 (Lazurite component)

Quartzite River Rock with Dendrites

Metamorphosed Quartz-rich Sandstone with Manganese Oxide (MnO2) inclusions

Honeycomb Calcite

Calcite (Calcium Carbonate, CaCO3)

Pink Granite (with Potassic Feldspar and Quartz)

Felsic Intrusive Igneous Rock (Granite)

Granite

Granite (a felsic intrusive igneous rock)

Milky Quartz

Silicon Dioxide (SiO2)

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Black Sapphire

Corundum (Al2O3 with iron and titanium impurities)

Kimberlite with Diamond

Kimberlite (Diamond formula: C)

Diorite (Polished River Pebble)

Diorite (Intermediate intrusive igneous rock)

Gneiss

Gneiss (Metamorphic rock composed primarily of quartz, feldspar, and mica)

Mica Schist with Quartz

Mica-Quartz Schist (Muscovite subclass)